Benzimide-azolon absonic acids and pbocess fob pbepabinor the same



. Reis'sued Feb; 18,1930

the formula:

' UNlTED, STATES PATE T orrlca v WILHELM KOLLE' AND @KARL STREITWOLF, or FRANKFORT -0N-THEMAIN, m; ALFRED FEHRLE, or sonEN-on-rHE-TAUNUs, GERMAN ASSIGNORS, BY MESNE ASSIGNMENTS, T0 WIN'IHROP 'GHEMICAL coMPANY; ornEw YORK, n.1,, A core PORA'IION OF NEW YORK :BENzIMInE-AzoLo v- ARSONIG Acrns AND Pnocnss ronrnnrlinme THE SAME No Drawing. OriginaI No. 1,674,368, dated June 19, 1928, Serial N0. 123,589, filed- July 19, 1926, and in Germany July 31, 1925.

By causing phosgene to act upon orthodiaminobenzenearsonic acids benzimidea zo lonarsomc acids are obtained, thus for mstance from '3.4-diaminobenzenearsonic acid the 3.4 benzimideazolonarsonic acid having prove to be of a considerably higher therapeutic value, which fact could not be foreseen, sinceBertheiIn states in Berichte vol. 45, page 2135, with reference to lnvestlgations and experiments made by F. Leupold v and others, that .4-dimethylaminophenylrarsonic acid and 4-amino-3-methyl-phenylarsonic acid have a lowertherapeutic'eliicacy than the p-arsanilic acid. Similar experiments were made" regarding dye-stuffs. Therefore the general conclusion was drawn thatthe entrance of a methyl group into those compounds impairs their therapeutic action.

But contrary to the experiments above referred to, the acids hereafter described are of a higher therapeutic efficacy than the nonsubstituted 3.4-benzimideazolonarsonic acid.

The following example illustrates our invention, but is not intended to limit it thereto:

11.6 parts by weight of '3-amino-4-methyl aminobenzenearsonic acid, obtained by reduction'of the corresponding nitroacid (see Bertheim-Berichte vol. 44 (1911) 3095 and Bauer-Berichte vol. 48 (1915) page 517 are dissolved in 210 parts by volume of a 2 N. solution of sodium acetate and while stirring phosgene is introduced, whereupon the benz- Application for reissue filed June 11, 1929. Serial No. 370,147.

(4-1nethyl)-imideazolonarsonic acid separates in the form ofcrystals,

The resulting acid is washed with water and recrystallized from Water or it ispurified by dissolving in dilute caustic soda solution and reprecipitating by means of hydro-.

chloric acid.

In an analogous manner from 3-chloro-4- nitrobenzenearsonic acid or 3-nitro-4-ch1orobenzenearsonic acid, the former prepared by treating 3-chloro-4-nitraniline with arsenic according to Bart, there are produced the corresponding homologues or alkylene substituted benzimideazolonarsonic acids by caus- A ing the first mentioned acids to act upon such comppunds as ethylamine propylamine, allylamine, benzylamine and by reducing subsequently the nitro. group and treating the redu'ctionproductso obtained with phosgene.

Such homologous or alkylene substituted benzimideazolonarsonic acids are for instance: v

3.4- benz (4 propyl) imideazolonarsonic acid which is rather difiicultly soluble in Water, soluble in methyl alcohol and insoluble in acetone.

3.4-benz- (4-allyl) -i1nideazolonarsonic acid which is capable of being recrystallized from water, insoluble in acetone and soluble in Wood-alcohol.

3.4 benz (4 benzyl) imideazolonarsonic acid which is very dilficultly soluble in water, more readily soluble in methyl alcohol and insoluble in acetone.

3.4 benz (3 methyl) imideazolonarsonic acid which is difiicultly soluble in methyl alcohol, capable of being recrystallized from water, insoluble in acetone.

We claim:

1. Process for preparing benzimideazolonarsonic acids, which consists in causing phosgene to act upon a benzenearsonic acid of the general formula:

alkyl, an unsaturated A ownin -can wherein R stands for zolonarsonic acids, which consists in causing phosgene to act upon a benzenearsonic acid of the formula:

wherein the Xs stand for amino groups, one of which is substituted bi alkyl, an unsaturated alkyl group or aral yl.

3. Process for preparing 3.4benz- (i-meth yl) -imideazolonarsonic acid, which consists 111 causing phosgene to act upon the compound of the formula:

4. As new products, the benzimideazolonarsonic acids of the formula:

wherein R stands for alkyl, an unsaturated alkyl group or aralkyl.

5. As new products, the henzimideazolonarsonic acids of the formula:

sown)- In testimony whereof, we aflix oursignatures.

WILH'ELM KOLLE.

KARL STREITWOLF. ALFRED FEHRLE. 

